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Atomically dispersed copper species on ceria for the low-temperature water-gas shift reaction

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Science China Chemistry 2021年第7期64卷 1103-1110页

作者： Jing Ning Yan Zhou wenjie shen State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

The structure of copper species,dispersed on nanostructured ceria(particles,rods and cubes),was analyzed by scanning transmission electron microscopy(STEM)and X-ray photoelectron spectroscopy(XPS).It was interestingly found that the density of surface oxygen vacancies(or defect sites),induced by the shape of ceria,determined the geometrical structure and the chemical state of copper *** dispersed species and monolayers containing few to tens of atoms were formed on ceria particles and rods owing to the enriched anchoring sites,but copper clusters/particles co-existed,together with the highly dispersed atoms and monolayers,on cubic *** atomically dispersed copper sites and monolayers interacted strongly with ceria,involving a remarkable charge transfer from copper to ceria at their *** activity for the low-temperature watergas shift reaction of the Cu/CeO_(2) catalysts was associated with the fraction of the positively-charged copper atoms,demonstrating that the active sites could be tuned by dispersing Cu species on shape-controlled ceria particles.

关键词： Cu/CeO_(2)catalysts ceria shape copper-ceria interface atomically dispersed copper sites monolayers low-temperature water-gas shift reaction

An Analysis of Life Strategies of Rural Wives in City——Based on Depth Interview of 65 Cases

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学术界 2014年第12期 273-279页

作者： shen wenjie Department of Social Work School of law Nanjing University of Finance and Economics

Through case study,this paper discusses the life strategies of the rural female who moved to city by getting married with urban male when they face all kinds of problems in their urban life,and analyzes the causes,ways and consequences of life strategies they choose. Finally it gives pertinent countermeasures which could help them improve their survival predicament in urban society.

关键词： rural female marriage immigrant urban life strategy

Urban Social Mobility Plight of City Wives from Countryside

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学术界 2015年第9期 280-285页

作者： shen wenjie Department of Social Work School of law Nanjing University of Finance and Economics Nanjing Jiangsu 210046

Through field investigation,this paper discusses the social mobility of city wives from countryside and analyses the causes of the upward social mobility plight of this group in urban *** author believes that city wives from countryside cannot continue to move upward in urban society because of their lack of culture capital and social *** break such plight of upward mobility for the group demands the system renovation.

关键词：城市社会农村妇女流动社会资本社会发展群体

Green rusts-derived iron oxide nanostructures catalyze NO reduction by CO

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Green Energy & Environment 2023年第2期8卷 499-508页

作者： Ping Wang Xiaoling Mou Yong Li wenjie shen Hangzhou Institute of Advanced Studies Zhejiang Normal UniversityHangzhou311231China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China

Green rusts with brucite-like layers of hydroxide intercalated with anions constitute a family of diverse precursors for the synthesis of iron oxides via dehydration,but precise structural control of the resulting oxides with respect to the size and shape at the nanometer level remains challenging due to the easy oxidation of the ferrous ***,we report a new synthetic strategy for the facile preparation of fibrous-like green rusts by using appropriate balancing anions(CO_(3)^(2-)and SO_(4)^(2-))in ethylene glycol to regulate the *** on the type of the intercalating anion,the green rusts were converted into hematite with fibrous-or plate-like shapes upon thermal *** evaluated in the reaction of NO reduction by CO,these iron oxides showed a prominent shape-dependent catalytic *** fibrous-like Fe_(2)O_(3)was much more catalytically active and structurally robust than the plate-like *** spectroscopic and microscopic characterizations on the nanostructured iron oxides revealed that the superior performance of the fibrous-like Fe_(2)O_(3)stemmed from a facile Fe_(2)O_(3)/Fe_(3)O_(4)redox cycle and a higher density of active sites for NO activation.

关键词： Green rust Hematite Morphology NO reduction by CO Redox cycle

Preparation of LaFe_(0.95)Pd_(0.05)O_3 perovskites and their catalytic performances in methane combustion

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Journal of Natural Gas Chemistry 2012年第2期21卷 113-118页

作者： Xiaojing Zhang Yong Li Huaju Li wenjie shen State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

The physic-chemical properties of LaFe0.95Pd0.05O3 perovskites were strongly dependent on the temperature of calcination. Most of the organic substances and inorganic impurities were readily removed at 723 K but single-phase and well crystallized perovskite structure was formed at 873 K. With further raising the calcination temperature, the crystallite size of LaFe0.95Pd0.05O3 increased considerably. The LaFe0.95Pd0.05O3 sample that calcined at 1073 K showed only comparable activity as the reference LaFeO3 catalyst, in particular below 923 K, but pre-treatment with the reaction gas at 1223 K resulted in significantly enhanced activity due to the generation of active PdO species on the surface. The hysteresis feature upon heating-cooling cycle further confirmed the strong interaction between Pd and LaFeO3 in the perovskite structure.

关键词： perovskite LaFe0.95Pd0.05O3 calcination temperature pre-treatment methane combustion

Interplay between geometric and electronic structures of Pt entities over TiO_(2) for CO oxidation

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Science China Chemistry 2024年第2期67卷 705-714页

作者： Xixiong Zhang Wen Shi Shaobo Han Yong Li wenjie shen School of Chemistry Dalian University of TechnologyDalian116024China State Key Laboratory of Catalysis Dalian Institution of Chemical PhysicsChinese Academy of SciencesDalian116023China

Monodispersed Pt colloids with a mean size of 2 nm were deposited uniformly on the {110} facets of a rod-shaped rutile TiO_(2),forming a well-defined Pt/TiO_(2) *** treatment of this precursor at elevated temperatures re-dispersed the Pt particles into clusters and ***-calcination at 673 K partially oxidized the Pt particle surface,while calcination at 773 K yielded Pt Oxclusters of 1.6 nm in 7–8 atomic *** calcination at 873 K formed a mixture of raft-like PtO_(x) clusters(1.6 nm,1–2 atomic layers) and cationic *** tested for CO oxidation at 373 K,the Pt particles showed a higher activity than the Pt Oxclusters,whereas the cationic single-atoms were much less *** H_(2)-reduction at 473 K converted the partially oxidized Pt particles into the metallic species,but they were encapsulated by TiO_(2)–xoverlayers because of the strong metal–support interactions,which decreased the activity dramatically.H_(2)-reduction of the PtO_(x) clusters at473 K enhanced the fraction of metallic Pt species without changing the size and geometry,and promoted the activity substantially.H_(2)-treatment of Pt single-atoms at 473 K increased the activity only moderately because most Pt species still kept at cationic *** results straightforwardly differentiated the catalytic behavior of Pt particles,clusters and single-atoms at the same metal loading and over the same TiO_(2) support,and further demonstrated that the electronic structures of Pt entities played a decisive role in the catalytic oxidation,in addition to the specified sizes.

关键词： Pt/TiO_(2)catalyst size effect Pt clusters active sites electronic structures CO oxidation

A systematic design of multifunctional lattice structures with energy absorption and phononic bandgap by topology and parameter optimization

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International Journal of Smart and Nano Materials 2023年第3期14卷 265-285页

作者： Hongling Ye wenjie shen Weiwei Wang Ran Tao Faculty of Materials and Manufacturing Beijing University of TechnologyBeijingPRChina College of Engineering Peking UniversityBeijing 100871PR China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijingPRChina

Lattice structure can realize excellent multifunctional charac-teristics because of its huge design space,and the cellular configuration directly affects the lattice structural performance and lightweight.A novel energy-absorbing multifunctional lat-tice structure with phononic bandgap is presented by topol-ogy and parameter optimization in this ***,the two-dimensional(2D)cellular configuration is lightweight designed by using independent continuous mapping(ICM)topology optimization *** 2D cell is reconstructed by geo-metric parameters and rotated into a three-dimensional(3D)cell by using chiral shape to achieve ***,the surrogated model with energy absorption as the object and first-order natural frequency as the constraint is estab-lished to optimize a parametric 3D cell based on the Response Surface Methodology(RSM).Finally,the lattice struc-tures are assembled with dodecagonal staggered arrange-ments to avoid the deformation interference among the adjacent *** addition,the lattice structural energy absorp-tion and bandgap characteristics are analyzed and *** to Kelvin lattice structure,the optimal lattice struc-ture shows significant improvement in energy absorption ***,the proposed design also performs well in damping characteristics of the high-frequency and *** lattice structural optimization design framework has great meaning to achieve the equipment structural light-weight and multi-function in the aerospace field.

关键词： Multifunctional lattice structure energy absorption phononic bandgap topology optimization parameter optimization

Co_3O_4 nanosheets:synthesis and catalytic application for CO oxidation at room temperature

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Science China Chemistry 2014年第6期57卷 873-880页

作者： LV YongGe LI Yong TA Na shen wenjie State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences

Hexagonal β-Co(OH)2 nanosheets with edge length of 50 nm and thickness of 10 nm were hydrothermally synthesized with the aid of *** calcination at 350°C in air,the β-Co(OH)2 nanosheets was converted into Co3O4 nanosheets with a similar *** analyses during the calcination process identified that the β-Co(OH)2 precursor was initially dehydrated to HCoO2 and subsequently transferred into *** being applied to catalyze CO oxidation at room temperature,the Co3O4 nanosheets exhibited a higher activity than the conventional spherical *** was perhaps related to the partial exposure of the{112}planes over the Co3O4 *** porous structure generated during the calcination process also provided significant amounts of surface defects,which might contribute to the enhanced catalytic activity as well.

关键词： Co3O4 nanosheets CO oxidation morphology-dependence nanocatalysis

Fabrication of rod-shaped β-FeOOH: the roles of polyethylene glycol and chlorine anion

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Science China Chemistry 2016年第7期59卷 895-902页

作者： Xuejiao Wei Xiaoling Mou Yan Zhou Yong Li wenjie shen State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences

β-FeOOH nanorods of 40 nm wide and 450 nm long were fabricated through precisely regulating the hydrolysis kinetics of Fe3＋ in polyethylene glycol and the concentration of C1- as the structure-directing agent. Detailed structural and chemical analyses of the intermediates during the synthesis identified that the strong interaction between PEG and Fe3＋ modulated the hydrolysis kinetics of Fe3＋and prevented the aggregation of β-FeOOH nanorods; while C1- provided sufficient nucleation sites, stabilized the hollow channel of β-FeOOH, and more importantly induced the growth of the nanorods along [001] direction.

关键词： β-FeOOH nanorods hydrolysis kinetics capping agent anisotropic growth